1. Field of the Invention
The present invention relates to a cylinder assembly, and more particularly to a cylinder assembly for a door lock and that has a simple and easily assembled structure.
2. Description of Related Art
With reference to FIG. 7, a conventional cylinder assembly for a door lock comprises a housing (90), a cylinder (93) and an actuating tongue (94). A through hole (91) is defined through the housing (90) for receiving the cylinder (93). The housing (90) has multiple apertures (92) radially defined in the housing (90) and communicating with the through hole (91). An upper lock pin (921) is moveably received in each respective aperture (92) and extends into the through hole (91). The cylinder (93) is rotatably received in the through hole (91) in the housing (90). A keyhole (not shown) is defined in a first end of the cylinder (93) for a key (97) inserting into the keyhole. An outer thread (932) is formed around a second end of the cylinder (93). Multiple apertures (933) are defined in the cylinder (93) and communicate with the keyhole. Each aperture (933) in the cylinder (93) is aligned with one of the apertures (92) in the housing (90). A lower lock pin (934) is received in each respective aperture (933) in the cylinder (93) and abuts the corresponding upper lock pin (921), and each lower lock pin (934) has a length different from that of the others. A driving pin (936) is moveably mounted in a hole (931) defined in the second end of the cylinder (93), and a spring (935) received in the hole (931) abuts the driving pin (936). A stub (937) with a diameter smaller than that of the driving pin (936) extends from the exposed end of the driving pin (936), such that a shoulder is formed between the driving pin (936) and the stub (937).
The actuating tongue (94) is securely attached to the second end of the cylinder (93) with a cap (96) and is connected to a latch (not shown) of the door lock. The cap (96) has an inner thread (961) to screw with the outer thread (932) on the cylinder (93), such that the cap (96) can securely be attached to the cylinder (93) by means of the engagement between the threads (932,961). A flange (not numbered) is formed on one end of the cap (96), and multiple recesses (962) are defined in the inner periphery of the flange. The stub (937) on the driving pin (936) extends into one of the recesses (962), and the shoulder on the driving pin (936) abuts the inner surface of the flange. A driven plate (95) is mounted around the tongue (94) and has a central hole (951) with a shape corresponding to the cross section of the actuating tongue (95), such that the tongue (94) can rotate with the driven plate (95). The driven plate (95) has two sides respectively abutting the flange on the cap (96) and a plate (941) formed on the tongue (94), such that the tongue (94) can be kept from releasing from the cylinder (93) by the driven plate (95) and the cap (96).
A notch (952) is defined in a periphery of the driven plate (95) and engages with the driving pin (936) on the cylinder (93). When the cylinder (93) is rotated, the driven plate (95) will rotate due to the engagement between the driving pin (936) and the notch (952) so that the tongue (94) will also rotate. The latch of the door lock will be actuated to lock into or unlock from a recess defined in the doorframe.
However, the conventional cylinder assembly has the following drawbacks:
1. To provide threaded portions (932,961) with enough structural strength to the cylinder (93) and the cap (96), the material for forming the cylinder (93) and the cap (96) must has a high structural strength. The cost for manufacturing the conventional cylinder assembly is high.
2. The structure of the conventional cylinder assembly is complicated, such that to assemble or disassemble the cylinder assembly is very troublesome.
To overcome the shortcomings, the present invention tends to provide a cylinder assembly to mitigate or obviate the aforementioned problems.
The main objective of the invention is to provide a cylinder assembly for a door lock and that can be easily assembled and disassembled. The cylinder assembly has a housing, a cylinder, an actuating tongue and a cap. The cylinder is securely held on the housing with a fastener and rotatably received in a through hole in the housing. A keyhole is defined in a first end of the cylinder, and a recess is defined in a second end of the cylinder. A curved channel is defined in a face defining the recess. The actuating tongue is attached to the second end of the cylinder. A connecting portion is formed on the first end of the tongue and is rotatably received in the recess in the cylinder. A protrusion protrudes from the first end of the actuating tongue and extends into the curved channel in the cylinder. The cap is mounted around the actuating tongue and secured to the second end of the cylinder. In such an arrangement, the cylinder can be easily assembled to or disassembled from the housing by means of attaching or removing the fastener. To assemble or to disassemble the cylinder assemble is easy, and the cost for manufacturing the cylinder assembly is low.